Conventional bags or sacks used for packaging products such as diapers are typically formed from a paperboard or plastic blank assembled in a rectangular open-ended configuration. The bags are filled with their package contents either manually or automatically in the production line. A separate sealing station is then employed to fold the open ends and seal them with an adhesive. Typical sealing systems comprise a complex combination of conveyors, folding mechanisms, tucking mechanisms, glue nozzles or brushes, motors, and cams to accomplish the folding and sealing of a package's open end. These types of systems therefore cannot be easily installed and incorporated into existing production lines and cannot accommodate bags having a broad range of sizes. Further, conventional systems typically produce packages having tucks and folds which are not precise causing poor quality seals.
Several attempts have been made in the prior art to overcome the problems of conventional sealing machines. For example, U.S. Pat. No. 3,213,591 to Feurstein et al. discloses an apparatus and method for folding and sealing the open end of a container after it has been filled with merchandise. In accordance with this disclosure, a swinging tucking member is used for tucking the container's sides to form top and bottom flaps, and a curved slot is used to fold the top flap down and the bottom flap up. An adhesive is applied during tucking and folding and the apparatus is adjustable to accommodate packages of different sizes.
U.S. Pat. No. 2,584,529 to Allen discloses a bag folding and sealing machine comprising a complex system of swinging tuck plates, folding rods, and cams and followers. The conveying mechanism in this reference temporarily stops at various points during the sealing process.
However, the prior art has not provided a satisfactory bag sealing system specifically adapted to automatically sealing the open end of a filled bag or sack as it comes directly off an existing production and packaging line. Conventional systems are not capable of producing consistent folds to form high quality seals or of quickly and easily adapting to various bag sizes.